Wu Shiji said in Li Zhuo Parallel Prose: "The principle of external treatment is the principle of internal treatment, and the medicine for external treatment is also the medicine for internal treatment. The difference is the law. "

The meaning of this sentence is: Chinese medicine should master the etiology and pathogenesis, emphasize syndrome differentiation and treatment, analyze the deficiency and excess of yin and yang cold and heat according to the viscera, and then give corresponding treatment. This is true for internal treatment, and so is external treatment. This is not just a cure for headache, but a cure for foot pain. External treatment is only used as local medicine, and external treatment and internal treatment should be treated equally. External treatment and internal treatment are just different ways and means of administration.

To put it more bluntly: the principle of treating diseases is still the same, and the drugs for treating diseases are still the same, but the methods are different.